JP6311278B2 - Heat dissipation member, manufacturing method thereof, and structure using heat dissipation member - Google Patents

Description

  The present invention relates to a heat radiating member and a structure, and more particularly to a heat radiating member and a structure that can be used for a heat pipe to which evaporation and condensation of hydraulic fluid are applied, and a method for manufacturing the heat radiating member.

A heat pipe is a fluid that evaporates (absorbs latent heat) in the high-temperature part, condenses (releases latent heat) in the low-temperature part, and circulates in the heat pipe, causing heat transfer from the high-temperature part to the low-temperature part. It is. Utilizing such vaporization (absorption of latent heat) and condensation (release of latent heat) of hydraulic fluid for heat dissipation and heat transport, heat pipes are used for various purposes such as cooling of devices such as CPUs.
In such a heat pipe, efficient circulation of the hydraulic fluid is important, and in order to disperse the condensed hydraulic fluid quickly in the high temperature part in the heat pipe without stagnation in the low temperature part, for example, It has been proposed to arrange the linear body along the inner wall surface (Patent Document 1) or to roughen the inner wall surface of the heat pipe (Patent Document 2).
On the other hand, portable devices typified by PCs and smartphones are becoming more sophisticated year by year, and the amount of heat generated from electronic components tends to increase. In particular, main semiconductor elements that operate portable devices are highly integrated with increasing functionality, and the amount of heat generated is increased. In addition, the amount of electric power required for the operation of the electronic device is also increasing, and the amount of heat generated from the battery is also increasing.

JP-A-5-106976 Japanese Unexamined Patent Publication No. 8-75381

However, in the heat pipe disclosed in Patent Document 1, a part of the hydraulic fluid passes over the striatum and flows down in a streak shape, and does not spread into a liquid film, thereby narrowing the area where the hydraulic fluid evaporates. There was a problem of becoming. Further, even in the heat pipe disclosed in Patent Document 2, when the roughening becomes large, there is a problem that the return of the hydraulic fluid is delayed, and the circulation efficiency of the hydraulic fluid is lowered, and heat exchange is hindered. It was. Moreover, the heat pipe of the structure currently disclosed by patent document 1 and patent document 2 also had the problem that thickness reduction for using for portable apparatuses, such as PC and a smart phone, was difficult.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a heat radiating member, a manufacturing method thereof, and a structure that enable a heat pipe having good circulation due to evaporation and condensation of hydraulic fluid. And

In order to solve such a problem, the heat dissipation member of the present invention has a base material and at least one through hole penetrating the base material, and the base material has an inner wall in the through hole. together is roughened, it possesses a protruding portion which inner wall protruding into the through-hole, the position of the tip of the projecting portion in the inner wall, so as to unevenly distributed on one surface of said substrate The through hole is out of the middle in the depth direction, and the opening size of the through hole on one surface side of the base material is smaller than the opening size of the through hole on the other surface side of the base material. The opening size at the portion where the tip of the protruding portion inside the hole is present is smaller than the opening size of the through hole on the one surface side of the substrate and the opening size of the through hole on the other surface side of the substrate. The configuration is as follows.

As another aspect of the present invention, the difference between the opening size of the through hole on the one surface side of the base material and the opening size at the site where the tip of the protruding portion inside the through hole exists is 15 to 200 μm. It was set as such a structure.
As another aspect of the present invention, the difference between the opening size of the through hole on the other surface side of the base material and the opening size at the site where the tip of the protruding portion inside the through hole exists is 15 to 200 μm. It was set as such a structure.
As another aspect of the present invention, the roughened inner wall has a configuration in which the surface roughness Ra is in the range of 1 to 3 μm.
As another aspect of the present invention, the roughened inner wall has a surface area ratio in the range of 1.5 to 2.5.
As another aspect of the present invention, the shape of the opening of the through hole in plan view is configured such that there are two or more bent portions on the inside.

The manufacturing method of the heat radiating member of the present invention includes a step of forming a resist layer having desired openings on both surfaces of a base material, and after etching the base material to a desired depth through one of the resist layers, Etching the base material through the resist layer to form a through hole, and subjecting the inner wall of the base material exposed in the through hole with the resist layer left to a roughening treatment. etching a step of applying, have a, a step of removing the resist layer, and the etching depth when etching the substrate via the resist layer of the one, the base material through the resist layer of the other It was so that configuration made different from the etching depth at the time of.

  As another aspect of the present invention, the roughening treatment is performed so that the surface roughness Ra of the inner wall is in the range of 1 to 3 μm and the surface area ratio is in the range of 1.5 to 2.5. did.

  The structure of the present invention includes a main body having an internal space along the stacking direction in which a plurality of the heat dissipation members of the present invention described above are stacked so that the positions of the through holes coincide with each other. Cover members respectively disposed so as to seal the internal space are provided on the two end faces where the openings are exposed.

As another aspect of the present invention, one of the cover members is configured to have a cooling fin.
As another aspect of the present invention, the heat radiating member has a plurality of through holes, and at least one of the cover members has a flow path for communicating the plurality of internal spaces of the main body with the main body. It was set as the structure which has in the surface side.

In the heat dissipation member of the present invention, the inner wall of the base material in the through hole is roughened, and the inner wall has a protruding portion that protrudes into the through hole. In this way, in a heat pipe or the like produced using a heat radiating member, a good circulation by evaporation and condensation of the working fluid can be obtained.
The structure of the present invention functions as a heat pipe or the like capable of efficiently radiating heat and transporting heat by encapsulating the working fluid in a sealed space present inside, thereby obtaining good circulation of the working fluid by evaporation and condensation. can do. Further, a thin structure can be formed by setting the size, shape, and number of layers of the heat dissipating member constituting the main body, and it can be used as a heat pipe in a portable device such as a PC or a smartphone.
The method for manufacturing a heat radiating member according to the present invention forms a protrusion on the inner wall of the base material exposed in the through-hole and makes the inner wall a rough surface, while roughening the other portion of the base material. Therefore, when the heat dissipating member is laminated by diffusion bonding, good bondability can be obtained.

FIG. 1 is a partial cross-sectional view for explaining an embodiment of a heat dissipation member of the present invention. FIG. 2 is a partial cross-sectional view for explaining another embodiment of the heat radiating member of the present invention. FIG. 3 is a view for explaining the opening size in the through hole of the heat dissipation member of the present invention. FIG. 4 is a diagram illustrating another example of a planar view shape of the opening of the through hole of the heat dissipation member of the present invention. FIG. 5 is a partial cross-sectional view for explaining an embodiment of the structure of the present invention. FIG. 6 is a partial cross-sectional view for explaining another embodiment of the structure of the present invention. FIG. 7 is a partial cross-sectional view for explaining another embodiment of the structure of the present invention. FIG. 8 is a partial cross-sectional view for explaining another embodiment of the structure of the present invention. FIG. 9 is a process diagram for explaining an embodiment of a method for producing a heat radiating member of the present invention. FIG. 10 is a process diagram for explaining another embodiment of the method for producing a heat radiating member of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the drawings are schematic or conceptual, and the dimensions of each member, the ratio of sizes between the members, etc. are not necessarily the same as the actual ones, and represent the same members. However, in some cases, the dimensions and ratios may be different depending on the drawing.
[Heat dissipation member]
FIG. 1 is a partial cross-sectional view for explaining an embodiment of a heat dissipation member of the present invention. In FIG. 1, the heat dissipation member 11 has a base material 12 and a through hole 14 penetrating the base material 12, and the base material 12 has a roughened inner wall 12 ′ in the through hole 14. The inner wall 12 ′ has a protruding portion 13 that protrudes into the through hole 14. In addition, although the number of through-holes 14 penetrating the base material 12 is one in the illustrated example, two or more through-holes 14 may be provided.

  The base material 12 constituting the heat radiating member 11 may be a material such as copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, brass, nickel, nickel alloy, chromium alloy, stainless steel, etc. In particular, any one of copper, copper alloy, aluminum, aluminum alloy and the like is preferable. The thickness of the base material 12 can be set in consideration of the structure produced using the heat radiating member 11, the structure of a heat pipe, the strength of the material used, the thermal conductivity, etc. It can set suitably in the range of 500 micrometers.

  Of the protrusions 13 provided on the inner wall 12 ′ of the base material 12, the position of the tip 13 a that protrudes most into the through hole 14 is in the middle of the depth direction of the through hole 14 in the illustrated example. That is, in the depth direction of the through-hole 14, a distance d1 from the tip 13a to the opening in the one surface 12a of the substrate 12 and a distance d2 from the tip 13a to the opening in the other surface 12b of the substrate 12 are It is equal. In the present invention, the position of the tip 13a of the protrusion 13 provided on the inner wall 12 'of the base 12 may be out of the middle of the through hole 14 in the depth direction. That is, in the heat radiating member 11 ′ shown in FIG. 2A, the distance d1 from the tip 13a to the opening on the one surface 12a of the base 12 is such that the opening on the other surface 12b of the base 12 from the tip 13a. It is larger than the distance d2. Further, in the heat dissipating member 11 ″ shown in FIG. 2B, the distance d1 from the tip 13a to the opening on the one surface 12a of the base 12 is such that the opening on the other surface 12b of the base 12 from the tip 13a. Thus, the retention of the working fluid can be controlled by appropriately setting the position of the tip 13a of the protrusion 13 provided on the inner wall 12 'of the base 12 as described above. In addition, when the heat dissipation member 11 has a plurality of through holes 14, the positions of the tips 13a of the protrusions 13 may be the same in all the through holes, and the arrangement of the through holes 14 in the heat dissipation member 11, etc. Accordingly, the position of the tip 13a of the protrusion 13 may be different.

  Thus, by providing the protruding portion 13 so that the inner wall 12 ′ of the base material 12 protrudes into the through hole 14, the opening dimension W at the portion where the tip 13 a of the protruding portion 13 inside the through hole 14 exists is The opening dimension Wa of the through hole 14 on the surface 12a of the substrate 12 is smaller than the opening dimension Wb of the through hole on the surface 12b of the substrate 12. The opening dimensions W, Wa, and Wb in the through hole 14 mean dimensions in the same direction in the plan view shape of the opening of the through hole 14. For example, when the plan view shape of the opening of the through hole 14 is a concentric circle as shown in FIG. 3A, the dimension in the same direction is, for example, the opening dimension W in the same direction indicated by an arrow in the figure. , Wa. Moreover, when the planar view shape of the opening part of the through-hole 14 is a similar elliptical shape as shown in FIG. 3B, the dimension in the same direction is, for example, an opening in the same direction indicated by an arrow in the figure. In this case, since the opening dimensions W, Wa, Wb change depending on the setting of the direction indicated by the arrow, the lengths of the opening dimensions W, Wa, Wb in the same direction are compared. The measurement of the opening dimensions W, Wa, Wb is a two-dimensional shape measuring instrument that can recognize the outline of the opening using reflected light and transmitted light, for example, the Nikon CNC image measurement system NEXI series. Can be used. In FIG. 3, the rough surface state of the inner wall 12 ′ of the base material 12 is omitted.

The opening dimensions Wa and Wb of the above-described through holes 14 take into consideration the structure manufactured using the heat radiating member 11, the structure of a heat pipe, the working fluid used, the strength of the material of the base material 12, the thermal conductivity, and the like. For example, it can be appropriately set within a range of 50 μm to 2 mm. Moreover, the opening dimension W in the site | part in which said front-end | tip 13a exists can be set so that the difference (Wa-W, Wb-W) with opening dimension Wa and Wb may be set to about 15-200 micrometers. If the difference between the opening dimension W and the opening dimensions Wa and Wb is less than 15 μm, the effect of providing the protruding portion 13 is not achieved, and if it exceeds 200 μm, the condensed hydraulic fluid is more than necessary in the protruding portion 13. There is a possibility that it may stay and adversely affect the circulation of the hydraulic fluid. When the heat dissipating member 11 has a plurality of through holes 14, the opening dimensions W, Wa, Wb of all the through holes may be the same, and according to the arrangement of the through holes 14 in the heat dissipating member 11, etc. The through-holes 14 may have different opening dimensions W, Wa, Wb.
The rough surface of the inner wall 12 ′ in the through-hole 14 in the substrate 12 preferably has a surface roughness Ra in the range of 1 to 3 μm. The surface roughness Ra can be measured using a contact type surface roughness meter or an optical interference type three-dimensional shape measuring instrument. When the surface roughness Ra is less than 1 μm, the effect of making the inner wall 12 ′ rough is not achieved, and when the surface roughness Ra exceeds 3 μm, condensed hydraulic fluid is required for the inner wall 12 ′ in the through hole 14. There is a possibility that the fluid stays in the above and adversely affects the circulation of the hydraulic fluid.

The rough surface of the inner wall 12 ′ in the through-hole 14 in the substrate 12 preferably has a surface area ratio in the range of 1.5 to 2.5. The surface area ratio is a ratio of the actually measured surface area including the shape of the surface roughness to the apparent area, and is a parameter called S-Ratio, and can be measured using an optical interference type three-dimensional shape measuring instrument. . If the surface area ratio is less than 1.5, the effect of roughening the inner wall 12 'is not achieved. If the surface area ratio exceeds 2.5, condensed hydraulic fluid is required for the inner wall 12' in the through hole 14. There is a possibility that the fluid stays in the above and adversely affects the circulation of the hydraulic fluid.
In FIG. 3 described above, a circle and an ellipse are exemplified as the planar view shape of the opening of the through hole 14. However, in the present invention, the planar view shape may be a rectangle or a polygon. Furthermore, the planar view shape of the opening part of the through-hole 14 may have two or more places bent inward. FIG. 4 shows an example of the shape of the opening of the through hole 14 in a plan view. In FIG. 4A, the shape of the opening of the through hole 14 has two bent portions 15 in plan view. It is what has. In FIG. 4B, the shape of the opening of the through-hole 14 in plan view has four inner bent portions 15 at four locations. Thus, when the plan view shape of the opening of the through-hole 14 has two or more locations that are bent inward, there are no bent portions (for example, in FIGS. 4A and 4B). Compared with the state (shown by dotted lines), the perimeter of the shape in plan view is increased, the area of the inner wall 12 ′ of the base material 12 in the through hole 14 is increased, and the spreading of the working fluid becomes easier. The circumference of the opening of the through hole 14 with the inner bent portion 15 is 1.1 times or more, preferably about 1.1 times or more with respect to the circumference of the opening of the through hole 14 when the inner bent portion 15 is not provided. It is suitable that it is 1.6 times or more. In FIG. 4, the rough surface state of the inner wall 12 ′ of the base material 12 is omitted.

Moreover, when the heat radiating member 11 of the present invention has a plurality of through holes 14, the openings in all the through holes may have the same shape in plan view, and depending on the arrangement of the through holes 14 in the heat radiating member 11 and the like. Thus, the shape of the opening in plan view may be different.
Such a heat radiating member 11 of the present invention has a roughened inner wall 12 ′ of the base material 12 in the through hole 14, and has a protruding portion 13 in which the inner wall 12 ′ projects into the through hole 14. Therefore, the working fluid can be appropriately retained and spread on the inner wall 12 ′, and good circulation by evaporation and condensation of the working fluid can be obtained in a structure, a heat pipe or the like manufactured using the heat radiating member 11.
The above-mentioned embodiment is an illustration and the heat radiating member of this invention is not limited to these embodiment.

[Structure]
FIG. 5 is a partial cross-sectional view for explaining an embodiment of the structure of the present invention. In FIG. 5, the structure 31 is formed by laminating a plurality (four in the illustrated example) of the above-described heat radiation member 11 of the present invention so that the positions of the through holes 14 coincide with each other. A main body 32 having an internal space 34 along the direction indicated by (2), and two end faces 32a and 32b at which the openings of the internal space 34 are exposed in the main body 32 so as to seal the internal space 34, respectively. Cover members 35, 37. In addition, the joining surface of the heat radiating members 11 and the joining surface of the main body 32 and the cover members 35 and 37 are shown by chain lines. The same applies to the following embodiments.

The number of stacked heat dissipating members 11 constituting the main body 32 of the structure 31 can be appropriately set in consideration of the thickness of the heat dissipating member 11, the thickness required for the main body 32, the volume required for the internal space 34, and the like. In addition, lamination | stacking of the thermal radiation member 11 can be performed by diffusion bonding, for example.
The cover members 35 and 37 constituting the structure 31 may be made of copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, brass, nickel, nickel alloy, chromium alloy, stainless steel, or the like, and conduct heat. In particular, it is preferably any one of copper, copper alloy, aluminum, aluminum alloy and the like, and the same material as the heat radiating member 11 is preferable. In the illustrated example, the cover members 35 and 37 have concave portions 35 a and 37 a at positions corresponding to the internal space 34 of the main body 32, and a sealed space is formed by the concave portions 35 a and 37 a and the internal space 34. . The main body 32 and the cover members 35 and 37 can be joined by diffusion joining, for example. Note that either one of the recesses 35a and 37a or both inner walls may be roughened.

In the illustrated example, the main body 32 is composed of the same heat radiating member 11. For example, the main body 32 is configured by stacking the heat radiating member 11 ′ or the heat radiating member 11 ″ as shown in FIG. Furthermore, the number, position, and shape of the opening in the plan view of the through hole are the same, but a plurality of types of heat dissipating members are different in the position of the tip 13a of the protrusion 13 provided on the inner wall 12 'of the base 12 The main body 32 may be configured by appropriately combining the above.
Moreover, the structure of this invention may have a fin for cooling in one cover member. A structure 31 shown in FIG. 6 includes a cooling fin 36 on the cover member 35. Such a cooling fin 36 may be made of copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, brass or the like, and is particularly made of copper, copper alloy, aluminum, aluminum alloy from the viewpoint of thermal conductivity. Either of them is preferable, and the same material as the cover member 35 is preferable. The number, shape, thickness, area, and arrangement pitch of the cooling fins 36 can be appropriately set in consideration of the material, the use of the structure, and the like.

In the example of the structure 31 described above, the main body 32 has one internal space 34, but may include two or more internal spaces 34. FIG. 7 is a partial cross-sectional view for explaining an example of such a structure of the present invention. In FIG. 7, a structure 41 is formed by laminating a plurality (four in the illustrated example) of the heat dissipating member 11 of the present invention having a plurality of through holes so that the positions of the through holes coincide with each other. The inner space 44 is sealed to the main body 42 having a plurality of inner spaces 44 along the direction indicated by the arrow a) and the two end faces 42a, 42b at which the openings of the inner space 44 are exposed. Cover members 45 and 47 arranged respectively.
The cover members 45 and 47 constituting the structure 41 have recesses 45a and 47a at positions corresponding to the plurality of internal spaces 44 of the main body 42, and a sealed space composed of the recesses 45a and 47a and the internal space 44. A plurality of are formed. The main body 42 and the cover members 45 and 47 can be joined by, for example, diffusion joining. The material of the cover members 45 and 47 can be the same as that of the cover members 35 and 37 described above. Note that either one of the recesses 45a, 47a or both of the inner walls may be roughened. One cover member, for example, the cover member 45 may have cooling fins.

FIG. 8 is a partial cross-sectional view for explaining another embodiment of the structure of the present invention. In FIG. 8, the structure 51 is formed by laminating a plurality (four in the illustrated example) of the heat dissipating member 11 of the present invention having a plurality of through holes so that the positions of the through holes coincide with each other. The main body 52 having a plurality of internal spaces 54 along the direction indicated by the arrow a) and the two end faces 52a, 52b at which the openings of the internal space 54 are exposed in the main body 52 are sealed. Cover members 55 and 57 arranged respectively.
The cover members 55 and 57 constituting the structure 51 have flow paths 55A and 57A for communicating with the plurality of internal spaces 54 of the main body 52 on the contact surface side with the end surfaces 52a and 52b of the main body 52. ing. That is, the cover members 55 and 57 have a structure in which the lid portions 55b and 57b are joined to the base portions 55a and 57a having shapes corresponding to the end faces 52a and 52b of the main body 52 via the pillar portions 55c and 57c. Channels 55A and 57A are configured between 57a and lid portions 55b and 57b. As a result, a sealed space including the flow paths 55A and 57A and the plurality of internal spaces 54 is formed, and the internal spaces 54 are in communication with each other via the flow paths 55A and 57A.

Such joining of the main body 52 and the cover members 55 and 57 can be performed by diffusion joining, for example. The material of the cover members 55 and 57 can be the same as that of the cover members 35 and 37 described above. Further, one cover member, for example, the cover member 55 may have a cooling fin.
Such a structure of the present invention is a heat pipe which can efficiently radiate heat and transport heat by enclosing the working fluid in a sealed space existing inside, thereby obtaining good circulation of the working fluid by evaporation and condensation. And so on. Further, a thin structure can be formed by setting the size, shape, and number of layers of the heat dissipating member constituting the main body, and it can be used as a heat pipe in a portable device such as a PC or a smartphone.
The above-described embodiments are examples, and the structure of the present invention is not limited to these embodiments.

[Method of manufacturing heat dissipation member]
FIG. 9 is a process diagram for explaining an embodiment of a method for producing a heat radiating member of the present invention. In FIG. 9, the production of the above-described heat radiation member 11 of the present invention will be described as an example.
In the manufacturing method of the present invention, resist layers 21 and 22 having desired openings 21a and 22a are formed on both surfaces 12a and 12b of the substrate 12 (FIG. 9A).
As described above, the base material 12 may be made of copper, copper alloy, aluminum, aluminum alloy, iron, iron alloy, brass or the like.
The resist layers 21 and 22 can be formed, for example, by applying a photosensitive resist on the substrate 12, exposing through a desired mask, and developing. Alternatively, it can be formed by laminating a photosensitive dry film on the substrate 12, and then exposing and developing through a desired mask. The resist layers 21 and 22 are preferably formed so that the openings 21a and 22a facing each other with the base material 12 in between match. Further, the dimensions of the openings 21a and 22a of the resist layers 21 and 22 can be appropriately adjusted in order to determine the opening dimensions Wa and Wb of the through-hole 14 to be formed.
Next, the base material 12 is simultaneously etched from both sides through the resist layers 21 and 22 to form the through holes 14 (FIG. 9B). The substrate 12 is etched by wet etching such as a dipping method or a spray method. On the inner wall 12 ′ of the base material 12 thus etched, a protruding portion 13 that protrudes into the through hole 14 is formed.

Next, with the resist layers 21 and 22 left, a roughening process is performed on the inner wall 12 ′ of the substrate 12 exposed in the through hole 14 (FIG. 9C). In this roughening treatment, a treatment liquid according to the material of the base material 12, for example, when the base material 12 is copper, a treatment liquid such as MEC etch bond CZ series manufactured by MEC Co., Ltd. can be used. When the substrate 12 is aluminum, a processing solution such as Mec Almat AR series manufactured by Mec Co., Ltd. can be used. Thus, by performing the roughening treatment without removing the resist layers 21 and 22, the both surfaces 12a and 12b of the substrate 12 can be protected. When the members are laminated by diffusion bonding, good bondability is obtained.
Thereafter, the resist layers 21 and 22 are removed to obtain the heat dissipating member 11 of the present invention (FIG. 9D).

FIG. 10 is a process diagram for explaining another embodiment of the method for producing a heat radiating member of the present invention. In this FIG. 10 as well, the production of the heat dissipating member 11 of the present invention will be described as an example.
In the manufacturing method of the present invention, the resist layers 21 and 22 having desired openings 21 a and 22 a are formed on both surfaces 12 a and 12 b of the substrate 12, and then the surface of the substrate 12 is covered with the resist layer 22. An etching barrier layer 23 is formed on 12b (FIG. 10A). The formation of the resist layers 21 and 22 can be the same as the above-described manufacturing method. The etching barrier layer 23 has a barrier property against the etching process of the base material 12 in a subsequent process, and can be formed of a material that can be removed while the resist layer 22 remains, for example, EC series manufactured by Sumilon Co., Ltd. Etc. can be used.
Next, the hole 14a is formed by etching from the surface 12a side of the substrate 12 to a desired depth through one resist layer 21 (FIG. 10B). The substrate 12 is etched by wet etching such as a dipping method or a spray method.
Next, the etching barrier layer 24 is formed so as to cover the resist layer 21 on the surface 12a of the substrate 12 in which the hole 14a is formed, and the etching barrier layer 23 formed on the surface 12b of the substrate 12 is removed. The resist layer 22 is exposed. The etching barrier layer 24 can be the same as the etching barrier layer 23 described above.

Next, etching is performed from the surface 12b side of the substrate 12 through the resist layer 22, and etching is performed until the etching barrier layer 24 is exposed in a desired range to form the hole 14b (FIG. 10C). Etching of the substrate 12 is also wet etching such as a dipping method or a spray method. In this etching, since the etching barrier layer 24 exists in the hole 14a formed in the previous step, the etching liquid is prevented from entering the hole 14a.
Next, by removing the etching barrier layer 24, the through hole 14 in which the hole 14a and the hole 14b communicate with each other is obtained, and the inner wall 12 ′ of the base material 12 thus etched is penetrated. A projecting portion 13 projecting into the hole 14 is formed (FIG. 10D). As described above, in the formation of the hole 14b, the etching liquid is prevented from entering the hole 14a, so that the etching that rounds the tip 13a is suppressed, whereby the tip 13a of the protrusion 13 is prevented. Becomes a sharp shape. Further, the position of the tip 13a of the protruding portion 13 in the depth direction of the through hole 14 can be controlled by adjusting the formation depth of the hole portion 14a.

Thereafter, as in the above-described embodiment, the inner wall 12 ′ of the base material 12 exposed in the through hole 14 is subjected to a roughening process (see FIG. 9C), and then the resist layers 21 and 22 are formed. By removing, the heat radiating member 11 of this invention is obtained (refer FIG.9 (D)).
Such a method of manufacturing a heat radiating member of the present invention forms a protrusion on the inner wall of the base material exposed in the through-hole and makes the inner wall rough, while roughening the other part of the base material. Since the surface treatment is not performed, good bondability can be obtained when the heat dissipation member is laminated by diffusion bonding.
The above-mentioned embodiment is an illustration and the manufacturing method of the heat radiating member of this invention is not limited to these embodiment.

Next, the present invention will be described in more detail by showing specific examples.
(Preparation of sample 1)
An oxygen-free copper base material (300 mm × 300 mm) having a thickness of 150 μm was prepared.
After laminating a photosensitive dry film (AQ-2558 manufactured by Asahi Kasei Co., Ltd.) on both surfaces of this substrate, the resist layer was formed by exposing through a desired mask and developing. The formed resist layer had 40000 circular openings with a diameter of 200 μm so as to be positioned at each intersection of the lattice shape at a pitch of 500 μm. Moreover, the opening part of each resist layer existed in the position which opposes through a base material.
Next, the substrate was simultaneously etched from both sides through a resist layer by spray etching using a ferric chloride solution as an etchant to form through holes.
Next, with the resist layer left, the inner wall of the base material exposed in the through hole was roughened. As the surface roughening treatment solution, Mec Etch Bond CZ manufactured by Mec Co., Ltd. was used.

Thereafter, the resist layer was removed using an aqueous 3% sodium hydroxide solution at a temperature of 50 ° C. to obtain a heat radiating member (sample 1).
A protrusion that protrudes into the through hole is formed on the inner wall of the base material exposed in the through hole of the heat radiating member (sample 1). The position of the tip of the protrusion is in the depth direction of the through hole. It was in the middle.
Further, the cross-sectional shape of the heat radiating member (sample 1) is observed using a two-dimensional shape measuring instrument (CNC image measuring system NEXI manufactured by Nikon Corporation), and the opening size of the through hole in the portion where the tip of the protruding portion exists. W, the opening dimension Wa of the through hole on one surface of the substrate, and the opening dimension Wb of the through hole on the other surface of the substrate (see FIGS. 1 and 3A for W, Wa, Wb) As a result, the opening dimension W was 200 μm, and the opening dimension Wa = Wb was 250 μm. Therefore, the difference (Wa−W, Wb−W) between the opening dimensions Wa and Wb and the opening dimension W was 50 μm.
Furthermore, the surface roughness Ra of the rough surface of the inner wall of the base material exposed in the through-hole of the manufactured heat dissipation member (sample 1) is measured with an optical interference type three-dimensional shape measuring instrument (Bartscan manufactured by Ryoka System Co., Ltd.). It was 2 micrometers as a result of measuring using R3300H Lite). Moreover, as a result of measuring the surface area ratio in the rough surface of the inner wall using the above-described optical interference type three-dimensional shape measuring instrument, the surface area ratio was calculated by the name of S-Raito and was 2.

(Preparation of Sample 2 to Sample 5)
The difference (Wa-W, Wb-W) between the opening dimensions Wa and Wb and the opening dimension W by changing the etching conditions (temperature and baume) for forming the through hole in the substrate is shown in Table 1 below. Except for the values shown, four types of heat dissipating members (Sample 2 to Sample 5) were produced in the same manner as Sample 1 described above.
(Preparation of Sample 6 to Sample 9)
Surface roughness Ra, surface area ratio of the inner wall rough surface of the base material is changed by changing the conditions (temperature of the processing solution and processing time) when the inner surface of the base material exposed to the through hole is roughened. Except that the values are as shown in Table 1 below, four types of heat dissipating members (Sample 6 to Sample 9) were produced in the same manner as Sample 1 described above.

(Preparation of sample 10)
The opening dimension Wa of the through hole on one surface of the substrate and the opening dimension Wb of the through hole on the other surface of the substrate are shown in FIG. 4A in a circle with a diameter of 250 μm instead of a circle with a diameter of 250 μm. A heat radiating member (sample 10) was produced in the same manner as the sample 1 except that the shape had two such inner bent portions. The circumference of the opening having the inner bent portion was 1.6 times the circumference of the circular opening.
(Preparation of sample 11)
A heat radiating member (sample 11) was produced in the same manner as the sample 1 except that the inner wall of the base material exposed in the through hole was not roughened.

(Evaluation)
Using the heat dissipating members of Sample 1 to Sample 11, 11 types of structures for evaluation were produced. That is, 20 heat dissipating members are processed into dimensions matching the size of the following measurement block, laminated so that the positions of the through holes coincide, and integrated by diffusion bonding to produce a main body. A cover member is joined to one end surface by diffusion bonding, pure water is poured into the internal space of the main body as a working fluid, and a cover member is immediately bonded to the other end surface of the main body by diffusion bonding to seal the internal space. It was set as the structure for evaluation.
Next, a copper measuring block of 100 mm × 100 mm and a height of 20 mm is prepared, the entire block is uniformly heated to 60 ° C., the periphery excluding the upper surface is covered with a heat insulating material, and the exposed upper surface is a structure for evaluation. One cover member side of the body was fixed with a heat conductive adhesive, left in the atmosphere at 20 ° C., and the temperature of the block after 3 minutes was measured. The results are shown in Table 1 below. The block temperature is the temperature at the center of gravity of the block, and was measured by installing a thermocouple in the measurement hole.

In Table 1, Sample 1 to Sample 5 are the results of testing the heat dissipation effect by changing the difference between the opening dimensions Wa and Wb and the opening dimension W without changing the surface roughness and the surface area ratio of the inner wall of the through hole. Samples 1 to 3 are cases where the difference between the opening dimensions Wa and Wb and the opening dimension W is 50 μm, 200 μm, and 20 μm, respectively, and a sufficiently high heat dissipation effect to lower the block temperature was obtained. On the other hand, when the difference between the opening dimensions Wa, Wb and the opening dimension W is 300 μm and 10 μm, the block temperature is not lowered and the heat radiation effect is insufficient.
Sample 10 has the same surface roughness and surface area ratio of the inner wall of the through hole as Samples 1 to 5, but has two inner bent portions whose plan view shape of the through hole is as shown in FIG. However, the difference between the opening dimensions Wa and Wb and the opening dimension W is 100 μm, respectively, and a sufficiently high heat dissipation effect was obtained as in Samples 1 to 3.

  Sample 6 to Sample 9 and Sample 11 are the results of testing the heat dissipation effect by fixing the difference between the opening dimensions Wa, Wb and the opening dimension W to 100 μm and changing the surface roughness and surface area ratio of the inner wall of the through hole. is there. In addition, the sample 11 is a sample which did not roughen the inner wall of the through hole. Samples 6 and 7 had surface roughness Ra of 1 μm and 3 μm, respectively, and surface area ratios of 1.5 and 2.5, respectively, and the heat dissipation effect of lowering the block temperature was sufficiently high. On the other hand, the sample 8 is a sample having a surface roughness Ra of 0.5 on the inner wall of the through hole and a surface area ratio of 1 and a small surface roughness, and the sample 9 has a surface roughness Ra of 4 on the inner wall of the through hole. No. 3 and a sample having a large surface roughness, all of which had an insufficient heat dissipation effect. Furthermore, sample 11 was a sample that was not subjected to the roughening treatment of the inner wall of the through hole, but the decrease in the block temperature was small and the heat dissipation effect was insufficient.

  It can be used to manufacture various devices and equipment that require heat dissipation and heat transport.

11, 11 ', 11 "... Radiating member 12 ... Base material 12' ... Inner wall 13 ... Protruding part 13a ... Tip of protruding part 14 ... Through hole 31, 41, 51 ... Structure 32, 42, 52 ... Main body 34, 44 54 ... Internal space 35, 37, 45, 47, 55, 57 ... Cover member 36 ... Cooling fins 55A, 57A ... Flow path

Claims (11)

A substrate and at least one through-hole penetrating the substrate;
The substrate with an inner wall within the through-hole is roughened, possess a protruding portion which inner wall protruding into said through hole,
The position of the tip of the projecting portion on the inner wall is deviated from the middle in the depth direction of the through hole so as to be unevenly distributed on the one surface side of the base material,
The opening size of the through hole on the one surface side of the base material is smaller than the opening size of the through hole on the other surface side of the base material, and in the portion where the tip of the protruding portion inside the through hole exists. An opening dimension is smaller than the opening dimension of the said through-hole in the one surface side of the said base material, and the opening dimension of the said through-hole in the other surface side of the said base material, The heat radiating member characterized by the above-mentioned . The difference between the opening size of the through hole on the one surface side of the base material and the opening size at a portion where the tip of the protruding portion inside the through hole exists is 15 to 200 µm. Item 2. The heat dissipating member according to Item 1. The difference between the opening dimension of the through hole on the other surface side of the base material and the opening dimension at a portion where the tip of the protruding portion inside the through hole exists is 15 to 200 µm. Item 2. The heat dissipating member according to Item 1.   The heat radiating member according to claim 1, wherein the roughened inner wall has a surface roughness Ra in a range of 1 to 3 μm.   The heat radiating member according to claim 1, wherein the roughened inner wall has a surface area ratio in a range of 1.5 to 2.5.   The heat radiation member according to any one of claims 1 to 5, wherein the opening of the through hole has two or more portions bent inward. Forming a resist layer having desired openings on both sides of the substrate;
Etching the base material to a desired depth through one of the resist layers, then etching the base material through the other resist layer to form a through hole;
Applying a roughening treatment to the inner wall of the base material exposed in the through-hole with the resist layer left;
Have a, a step of removing the resist layer,
Radiating member, wherein the etching depth, the Rukoto made different from the etching depth when etching the substrate via the resist layer of the other when etching the substrate via the resist layer of the one Manufacturing method. The heat dissipation according to claim 7 , wherein the roughening treatment is performed so that the surface roughness Ra of the inner wall is in a range of 1 to 3 μm and a surface area ratio is in a range of 1.5 to 2.5. Manufacturing method of member. The heat radiating member according to any one of claims 1 to 6, will be stacked so that the position of the through hole coincides, a body having an internal space along the stacking direction,
And a cover member disposed on each of the two end faces of the main body where the opening of the internal space is exposed to seal the internal space. The structure according to claim 9 , wherein one of the cover members has a cooling fin. The heat dissipation member has a plurality of through holes, and at least one of the cover members has a flow path on the contact surface side with the main body for communicating with the plurality of internal spaces of the main body. The structure according to claim 9 or 10 .

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